Observing Mitosis with Fluorescence Microscopy

Metaphase

Presented in the digital image above is a composite of mitotic rat kangaroo cells showing only the spindle assembly and chromosomes. Fibers comprising the mitotic spindle are functionally divided into two species. The polar fibers extend to the center of the spindle pole towards the metaphase plate, while the chromosomal fibers travel from individual condensed chromosomes to the poles. Chromosomal fibers (also referred to as kinetochore fibers) are attached to the chromosomes at the kinetochores, which form on opposite sides of the centromere. During metaphase, the chromosomes are gradually aligned at the metaphase plate by the mitotic spindle.